Pulp-digester for paper-making



(No Model.)

o. C. SPRING-RR.

4PULP DIRRSTRR POR PAPRR MAKING. No. 335,046. Patented Jan. 26, 1886.

llaman @raras Partnr narnia..

CHARLES C. SPRINGER, OF YARMOUIH, ASSIGNOR TO THE AMERICAN SULPHITE PULP COMPANY, OF PORTLAND, MAINE.

PULPDlGESTER FOR PAPER-MAKING SPECIFICATION forming part of Letters Patent No. 335,046, dated January 26, 1886.

l Application filed July 22, 1885. SerialNo.172,308. (No model.)

In the treatment of wood and other fiberyielding material for the production of ber for paper-pulp and other purposes the Wood or other material to be disintegrated is placed in a metal boiler, and for rapidity of action and cheapness the wood or other material is subjected to the action of an acid. In this class of apparatus, to avoid the destruction of the boiler and discoloration of the liber or pulp, theboiler has to be lined with lead or other acid-resisting metal, which, as now used, is applied in sheets, plates, or sections, and when placed in the boiler the edges of the sheets, plates, or sections used are united by solder or by fusing together the metal at the meeting edges, such operation requiring the employment of a blow-pipe within the boiler, which is slow and laborious, and consequently expensive, and so also the removal of a plate or section for repair, as is frequently necessary, requires very considerable time.

The object of my invention is to avoid this soldering, yet make liquid-tight joints, and this I have accomplished.

This invention has for its object to coniine a lead or acid-resisting lining in placein a metal boiler used for treatment of material in the manufacture of fiber for wood-pulp and other purposes, and this without the use of a blowpipe. To accomplish this, I have placed between or at the edges of the plates, sheets, or sections of the lead lining, or so as to overlap the edges of the sections or plates of lead used, an acid-resisting packing, preferably composed of asbestus or kindred material, and over this packing which covers the meeting or adjacent edges ofthe lead lining I have applied staystrips coated or covered with lead or other equivalent acid-resistin g compound, and I have secured these stay-strips iirmly in place by means of bolts composed of or covered with an acid-resisting metal, the said bolts being extended through the said stay-strips and the lining, and also through the shell of the boiler.

Figure l represents a portion or" the interior of a boiler for the treatment of woodl or other material in the manufacture of liber for paperpulp or other purpose, the stay-strips being partially broken out to show the packing below; and Fig. 2 is a partialsection inthelinexx.

Referring to the drawings, A represents part of the metallic shell of a boiler, which may be of any shape commonly used in the manufacture of paper-pulp or for the treatment of liber, the said boiler being composed in practice of sheets or plates of metal riveted together into cylindrical or into somewhat spherical shape.

The lead lining herein shown is of that form known as compound lining,7 it being the invention of one John Maken, the said lining being composed of a perforated foundationplate, a-such as iron coated on both sides, or it may be coated on but one side with lead or an acid-resisting compound, b, containing lead, which is united to the said foundationplate by casting in a mold.

In practice the edges of the plates or sections of the lead lining or the acid-resisting lining have been soldered or burned together after placing the plates or sections within the boiler-shell. To obviate this and cheapen the construction of the apparatus and improve its operation, I apply an acid-resisting packing, c, preferably asbestus, between or at the contiguous edges of the sheets, plates, or sections of the lead lining, the said packing being shown in Fig. 2 by heavy black lines, it lling the spaces left between the opposed or adjacent edges of the separate plates or sections of the lining, and preferably the said packing will be made to more or less overlap the said plates from the edges backward, as shown in Fig. 2`

by the heavy black line t.

The lead lining applied to the boiler in sections or squares is secured therein after the introduction of the packing, as described, by means of stay-strips B, composed, preferably, of a perforated metal band or bar, e, connected or covered with lead or other acid-resisting metal, f,the same being applied,prefcrably,by casting in a mold.

' The boiler-shell and the lead lining in the line of its meeting edges and the packing are provided withaseries of coinciding bolt-holes, and the said strips are also provided with a series of bolt-holes at corresponding distances apart, that when the stay-strips are put in place, as described, the said holes may be entered by the shanks of the bolts C, the shank of each bolt receiving a nut, C', as in Fig. 2, by which to draw the head of the bolt firmly down upon the staystrip and cause it to rmly clamp the contiguous edges of the lining to the inner wall of the boiler-shell. This bolt G'will in practice be made either of an acid-resisting metal or of other metal covered with lead wherever the bolt is liable to come in contact with the acid, the lead being shown by the letter g. Preferably Ishall introduce packing of asbestus or other acid-resisting material between the under sides of the heads of the bolts and the stay-strips, as shown ath, Fig. 2.

Instead of the particular lead lining herein shown and denominated in theinarket as a compound lining,77 and not specifically of my invention, I may employ sheet-lead or sheets or plates of lead or other acid-resisting metal, and instead of the particularstay-strip I may employ astrip of metal having sh eet-lead folded about it and lapped at the inner side of the Strip.

The use of a packing such as described obviates soldering the edges of the lining plates or sections in place in the boiler, and enables the lining to be readily repaired, when desired, by simply removing the nuts and withdrawing the bolts.

I claim- .i 1. The boiler-shell and sheets, plates, orsections of lining placed therein, and an acid-re sisting packing placed at the joints of the lin.

CHARLES C. SPRINGER.

Witnesses:

G. W. GREGORY, XV. H. SrGsroN. 

